A decoding unit for decoding a signal modulating a plurality of symbols wherein each symbol carries a plurality of information which are code-division multiplexed in the time domain and in the frequency domain and wherein each information is associated with a known sequence of phase rotations, the phase in the known sequence varying deterministically between the plurality of symbols.The decoding unit first performs a phase rotation of the received plurality of symbols, then performs the time-domain despreading operation and finally performs the frequency-domain despreading operation.A processor, a receiver, a method and a computer program are also claimed.